Vehicle powertrain systems and vehicle auxiliary drive methods, devices, and equipment

Abstract

This application relates to the field of vehicles and discloses a vehicle powertrain system and a vehicle auxiliary drive method, device, and equipment, including: determining a base speed based on the pressure error between the reference value and the actual value of the outlet pressure of the hydraulic pump in the current cycle in the vehicle's auxiliary hydraulic system using a pressure loop controller; determining a feedforward compensation speed based on the change in the reference value of the outlet pressure between the current and previous cycles, the load flow demand of the hydraulic pump in the current cycle, and the estimated value of the system leakage flow; determining an optimal efficiency speed by optimizing the overall efficiency of the hydraulic motor and the hydraulic pump; obtaining a reference value of the hydraulic motor speed by weighted fusion of the base speed, the feedforward compensation speed, and the optimal efficiency speed; and determining a reference value of the shaft current based on the speed error between the reference value and the actual value of the hydraulic motor speed using a speed loop controller, so as to control the current of the hydraulic motor through a shaft current loop controller and a shaft current loop controller, thereby avoiding the situation of difficult low-speed control and severe load impact.

Description

Technical Field

[0001] This application relates to the field of vehicles, and more particularly to a vehicle power system and a vehicle auxiliary drive method, device, and equipment. Background Technology

[0002] Currently, auxiliary hydraulic systems are being used more and more widely in large vehicles, large engineering vehicles, and other vehicles.

[0003] In pursuit of high efficiency and energy saving, and to reduce energy consumption, more and more auxiliary hydraulic systems are abandoning the traditional mechanical drive mode and turning to electric drive systems. Electric drive systems can provide stable power to auxiliary hydraulic systems, effectively improving energy utilization efficiency.

[0004] However, existing electro-hydraulic solutions still have significant problems in practical applications: the auxiliary hydraulic system is difficult to control at low speeds and experiences severe load shocks. Summary of the Invention

[0005] The purpose of this application is to provide at least one vehicle power system and vehicle auxiliary drive method, device, and equipment, which can at least solve the problems of difficult low-speed control and severe load impact in auxiliary hydraulic systems, and at least avoid the situation of difficult low-speed control and severe load impact in auxiliary hydraulic systems.

[0006] In a first aspect, this application provides a vehicle assisted driving method, comprising: Based on the pressure error between the reference value and the actual value of the outlet pressure of the hydraulic pump in the current cycle in the vehicle's auxiliary hydraulic system, the base speed of the current cycle is determined using a pressure loop controller. Based on the change in the reference value of the outlet pressure between the current cycle and the previous cycle, the estimated value of the load flow demand of the hydraulic pump in the current cycle, and the estimated value of the system leakage flow, the feedforward compensation speed in the current cycle is determined. The optimal efficiency speed for the current cycle is determined by optimizing the combined efficiency of the hydraulic motor driving the hydraulic pump and the hydraulic pump itself. The reference value of the hydraulic motor speed for the current cycle is obtained by weighted and fused the base speed, the feedforward compensation speed, and the optimal efficiency speed. Based on the speed error between the reference value and the actual value of the hydraulic motor speed in the current cycle, the speed loop controller is used to determine the current cycle. Reference value for shaft current; Based on the current cycle Reference value and actual value of shaft current Shaft current error, and based on the current cycle Reference value and actual value of shaft current Shaft current error, through Axis current loop controller and The shaft current loop controller controls the current of the hydraulic motor to drive the hydraulic pump.

[0007] Optionally, before obtaining a reference value for the current cycle hydraulic motor speed by weighted fusion of the base speed, the feedforward compensation speed, and the optimal efficiency speed, the method further includes: Based on the pressure error of the current cycle, determine the weighting coefficient corresponding to the base rotation speed; Based on the weighting coefficient corresponding to the base rotation speed, determine the weighting coefficient corresponding to the feedforward compensation rotation speed in the current cycle; Based on the weighting coefficients corresponding to the base speed and the feedforward compensation speed, the weighting coefficient corresponding to the optimal efficiency speed is determined. The weighted fusion of the base speed, the feedforward compensation speed, and the optimal efficiency speed to obtain a reference value for the hydraulic motor speed in the current cycle includes: Based on the determined weighting coefficients corresponding to the base speed, the feedforward compensation speed, and the optimal efficiency speed, the base speed, the feedforward compensation speed, and the optimal efficiency speed are weighted and summed to obtain a reference value for the hydraulic motor speed in the current cycle.

[0008] Optionally, the overall efficiency includes the product of the hydraulic motor efficiency and the hydraulic pump efficiency; The step of determining the optimal efficiency speed by optimizing the combined efficiency of the hydraulic motor driving the hydraulic pump and the hydraulic pump itself includes: determining the optimal motor speed when the hydraulic motor has the best efficiency under the current required torque based on the motor efficiency graph; determining the optimal pump speed when the hydraulic pump has the best efficiency based on the efficiency characteristics of the hydraulic pump; and weightedly fusing the optimal motor speed and the optimal pump speed to obtain the optimal efficiency speed; or... The step of determining the optimal efficiency speed by optimizing the overall efficiency of the hydraulic motor driving the hydraulic pump and the hydraulic pump includes: selecting the motor speed that minimizes motor losses from all motor speeds in the motor efficiency graph based on the current required torque, the rated torque of the hydraulic motor, and the base speed of the current period, as the optimal motor speed when the hydraulic motor efficiency is optimal under the current required torque; determining the optimal pump speed when the hydraulic pump efficiency is optimal based on the efficiency characteristics of the hydraulic pump; and weightedly fusing the optimal motor speed and the optimal pump speed to obtain the optimal efficiency speed.

[0009] Optionally, determining the feedforward compensation speed for the current period based on the change in the reference value of the outlet pressure between the current period and the previous period, the estimated value of the load flow demand of the hydraulic pump in the current period, and the estimated value of the system leakage flow includes: Based on the estimated load flow demand of the hydraulic pump in the current cycle and the estimated system leakage flow, the first compensation speed is determined; The second compensation speed is determined based on the change in the reference value of the outlet pressure between the current cycle and the previous cycle. Based on the first compensation speed and the second compensation speed, the feedforward compensation speed for the current cycle is determined.

[0010] Optionally, before determining the feedforward compensation speed for the current period based on the change in the reference value of the outlet pressure between the current period and the previous period, the estimated value of the load flow demand of the hydraulic pump in the current period, and the estimated value of the system leakage flow, the following steps are also included: Based on the pressure dynamic model of the hydraulic pump, the estimated value of the load flow demand in the current period, and the estimated value of the system leakage flow in the previous period, the estimated value of the system leakage flow in the current period is calculated. The pressure dynamic model is an equation used to describe the change of the outlet pressure of the hydraulic pump over time. The pressure dynamic model is related to the hydraulic motor speed, load flow demand, and system leakage flow.

[0011] Optionally, based on the pressure dynamic model of the hydraulic pump, the estimated value of the load flow demand in the current period, and the estimated value of the system leakage flow in the previous period, the estimated value of the system leakage flow in the current period is calculated, including: calculating the flow residual based on the pressure dynamic model and the estimated value of the system leakage flow in the current period; calculating the product of the flow residual and the adaptive gain; and summing the product with the estimated value of the system leakage flow in the previous period to obtain the estimated value of the system leakage flow in the current period; or, The estimated value of the system leakage flow rate for the current period is: ; in, Indicates the current period. Indicates the previous period. This represents an estimated value of the system leakage flow rate from the previous period. This represents an estimate of the load traffic demand for the current period. This represents an estimated value of the system leakage flow rate for the current period. Indicates adaptive gain. The inner value represents the flow residual. This indicates the displacement of the hydraulic pump. This represents the actual value of the hydraulic motor's rotational speed. This indicates the total volume from the pump outlet to the actuator cavity. Indicates the elastic modulus of the oil; This indicates the volumetric efficiency of the hydraulic pump; This represents the actual value of the hydraulic pump's outlet pressure. The rate of change of the outlet pressure is calculated based on the pressure dynamic model. Indicates time.

[0012] Optionally, the weighting coefficient corresponding to the base speed in the current period. for: ; in, Indicates the current period. This indicates the pressure error in the current cycle. Indicates the sensitivity coefficient; The weighting coefficient corresponding to the feedforward compensation speed in the current cycle for: ; The weighting coefficient corresponding to the optimal efficiency speed in the current cycle for: .

[0013] Optionally, the feedforward compensation speed in the current cycle is: ; in, Indicates the current period. Indicates the previous period. This indicates the feedforward compensation speed in the current cycle. This represents an estimate of the load traffic demand for the current period. This represents an estimated value of the system leakage flow rate for the current period. This represents a reference value for the export pressure in the current cycle. This represents a reference value for the export pressure mentioned in the previous period. This indicates the change in the reference value of the outlet pressure. This indicates the displacement of the hydraulic pump. This indicates the volumetric efficiency of the hydraulic pump. Indicates the elastic modulus of the oil. This indicates the total volume from the pump outlet to the actuator cavity. Indicates the duration of the period; This is the first compensation speed. This is the second compensation speed.

[0014] Optionally, before determining the base speed of the current cycle using the pressure ring controller, the method further includes: determining the parameters of the pressure ring controller for the current cycle based on the pressure error and the rate of change of the pressure error in the current cycle, wherein the pressure ring controller is a proportional-integral controller and the parameters of the proportional-integral controller include a proportional coefficient and an integral coefficient. The proportional coefficient mentioned in the current period for: ; in, Indicates the basic proportionality coefficient. This indicates the maximum adjustment amount of the proportional coefficient. Indicates the current period. This indicates the pressure error for the current cycle. The scale factor representing the pressure error; The integral coefficients for the current period for: ; ; in, Indicates the integration time. This represents the initial integration time constant. This indicates the rate of change of the current periodic pressure error. This represents the maximum rate of change of the pressure error. Indicates time.

[0015] Secondly, this application provides a vehicle powertrain system, including: an electric drive system, the electric drive system comprising: Multiple motors, including at least one auxiliary motor, the at least one auxiliary motor including at least one hydraulic motor, the hydraulic motor being used to drive a corresponding hydraulic pump in an auxiliary hydraulic system; A control unit is configured to perform, for each of the hydraulic motors, the vehicle auxiliary drive method described above.

[0016] Optionally, the plurality of motors further includes at least one traction motor, and the electric drive system further includes: a DC bus, the DC bus including a first DC bus on the high-voltage side and at least one second DC bus on the low-voltage side, the second DC bus being connected to the first DC bus via a corresponding DC-DC module; a main drive system, the main drive system being provided with the at least one traction motor, the traction motor being connected to the first DC bus via a corresponding inverter, at least a portion of the at least one traction motor being provided with a corresponding first charging / discharging interface, the first charging / discharging interface being connected to the neutral point of the stator winding of the corresponding traction motor and to the negative or positive terminal of the first DC bus; an auxiliary system, the auxiliary system being provided with at least one auxiliary motor, the auxiliary motor being connected to a second DC bus via a corresponding inverter, at least a portion of the at least one auxiliary motor being provided with a corresponding second charging / discharging interface, the second charging / discharging interface being connected to the neutral point of the stator winding of the corresponding auxiliary motor and to the negative or positive terminal of the second DC bus where the corresponding auxiliary motor is located; the first charging / discharging interface and the second charging / discharging interface are used to connect to the charging / discharging object; and / or, The vehicle powertrain system further includes a multi-source hybrid power unit; the multi-source hybrid power unit is used to supply power to the DC bus, and includes at least one engine, at least one power battery and grid wiring; the engine and the grid wiring supply power to the first DC bus, and the power battery supplies power to the corresponding second DC bus.

[0017] Thirdly, this application provides a vehicle auxiliary drive device, comprising: The base speed determination module is used to determine the base speed for the current cycle based on the pressure error between the reference value and the actual value of the outlet pressure of the hydraulic pump in the vehicle's auxiliary hydraulic system during the current cycle, using a pressure loop controller. The compensation speed determination module is used to determine the feedforward compensation speed for the current cycle based on the change in the reference value of the outlet pressure between the current cycle and the previous cycle, the estimated value of the load flow demand of the hydraulic pump in the current cycle, and the estimated value of the system leakage flow. The efficiency speed determination module is used to determine the optimal efficiency speed for the current cycle by optimizing the combined efficiency of the hydraulic motor driving the hydraulic pump and the hydraulic pump. The speed fusion module is used to weight and fuse the base speed, the feedforward compensation speed and the optimal efficiency speed to obtain a reference value of the hydraulic motor speed in the current cycle. The current reference determination module is used to determine the current cycle based on the speed error between the reference value and the actual value of the hydraulic motor speed in the current cycle, using the speed loop controller. Reference value for shaft current; The hydraulic drive module is used to drive the system based on the current cycle. Reference value and actual value of shaft current Shaft current error, and based on the current cycle Reference value and actual value of shaft current Shaft current error, through Axis current loop controller and The shaft current loop controller controls the current of the hydraulic motor to drive the hydraulic pump.

[0018] Fourthly, this application provides an electronic device, comprising: At least one processor; and, A memory communicatively connected to the at least one processor; wherein, The memory stores instructions that can be executed by the at least one processor to enable the at least one processor to perform the vehicle assisted drive method as described above.

[0019] The advantages of this application compared to the prior art are: In the vehicle auxiliary drive method of this application, based on the pressure error between the reference value and the actual value of the outlet pressure of the hydraulic pump in the current cycle of the vehicle's auxiliary hydraulic system, a pressure loop controller is used to determine the base speed of the current cycle; based on the change in the reference value of the outlet pressure between the current cycle and the previous cycle, the estimated value of the load flow demand of the hydraulic pump in the current cycle, and the estimated value of the system leakage flow, the feedforward compensation speed of the current cycle is determined; by optimizing the overall efficiency of the hydraulic motor and the hydraulic pump driving the hydraulic pump, the optimal efficiency speed of the current cycle is determined; the base speed, the feedforward compensation speed, and the optimal efficiency speed are weighted and fused to obtain the reference value of the hydraulic motor speed of the current cycle; based on the speed error between the reference value and the actual value of the hydraulic motor speed of the current cycle, a speed loop controller is used to determine the speed of the current cycle. Reference value for shaft current; based on the current cycle. Reference value and actual value of shaft current Shaft current error, and based on the current cycle Reference value and actual value of shaft current Shaft current error, through Axis current loop controller and The shaft current loop controller controls the current of the hydraulic motor to drive the hydraulic pump. In this way, it can comprehensively consider the hydraulic pump outlet pressure, load flow demand, system leakage status, and the overall efficiency of the hydraulic pump and hydraulic motor, dynamically optimize the reference value of the hydraulic motor speed, and realize multi-level closed-loop coordinated control of pressure loop, speed loop, and dual current loop. This avoids the situation of difficult low-speed control and severe load impact in the auxiliary hydraulic system.

[0020] It is understood that the beneficial effects of the second to fourth aspects mentioned above can be found in the relevant descriptions in the first aspect mentioned above, and will not be repeated here. Attached Figure Description

[0021] One or more embodiments are illustrated by way of example with reference to the accompanying drawings, and these illustrative descriptions do not constitute a limitation on the embodiments.

[0022] Figure 1 This is a schematic diagram of a vehicle powertrain system in the prior art; Figure 2 This is a flowchart of a vehicle assisted driving method provided in one embodiment of this application. Figure 1 ; Figure 3 This is another embodiment of the control topology for a hydraulic motor provided in this application; Figure 4 This is a schematic diagram of the structure of a vehicle powertrain system provided in another embodiment of this application. Figure 1 ; Figure 5 This is a schematic diagram of the structure of a vehicle powertrain system provided in another embodiment of this application. Figure 2 ; Figure 6 This is a schematic diagram of a vehicle auxiliary drive device provided in another embodiment of this application; Figure 7 This is a schematic diagram of the structure of an electronic device provided in another embodiment of this application. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the various embodiments of this application will be described in detail below with reference to the accompanying drawings. However, those skilled in the art will understand that many technical details have been provided in the various embodiments of this application to help readers better understand this application. However, the technical solutions claimed in this application can be implemented even without these technical details and various changes and modifications based on the following embodiments. The division of the various embodiments below is for the convenience of description and should not constitute any limitation on the specific implementation of this application. The various embodiments can be combined with and referenced by each other without contradiction.

[0024] To facilitate understanding of the embodiments of this application, relevant information about vehicles will be introduced first.

[0025] Large vehicles and large engineering vehicles are typically used in closed, fixed environments such as ports, mines, and construction sites. Their daily operating conditions and road conditions are relatively fixed, generally following a cyclical operation mode. These vehicles typically have large load capacities and operate in harsh environments, frequently encountering icy, muddy, and slippery roads. Currently, large vehicles and large engineering machinery mostly employ electric drive systems with a single power source. Electric drive systems offer precise vehicle drive output control performance. The main components of an electric drive system include: an engine, a generator, a traction converter, and wheel motors. The traction converter includes a rectifier unit and an inverter unit. The wheel motors include a traction motor and a reducer. For example... Figure 1 As shown, this is an electric drive system for large vehicles and large construction machinery with a single power source. The diesel engine provides the power source, and the generator is mechanically coaxially connected to the diesel engine. The generator is controlled by the Electronic Control Unit (ECU). At different speeds of the diesel engine, it outputs different voltages. The rectifier unit converts the AC power input from the generator into DC power, and the inverter unit converts the DC power back into AC power to control the operation of the traction motor. When the traction motor is in braking operation, it feeds energy back to the DC link of the traction converter. The chopper switching control of the inverter unit dissipates the energy in the braking resistor.

[0026] With the development of new energy technologies, traditional vehicles and construction machinery, which use diesel engines as their power source, are gradually evolving into hybrid power systems that combine diesel engines with power batteries (such as lithium batteries and supercapacitors), hydrogen fuel cells, power grid connections, or multiple energy sources. Meanwhile, due to the high power, cost, and pollution associated with large vehicles and construction machinery, large engines are gradually being replaced by multiple smaller engines operating in parallel. Furthermore, with the emergence of electrification technologies, the addition of chargers in the closed environments of construction machinery and large mining trucks makes vehicle installation and layout difficult. Additionally, the large number of battery system branches and excessive capacity in large construction machinery can lead to excessively long charging times. As vehicle electrification technology develops, the application of hydraulic electrification in vehicles is becoming increasingly widespread, but instability in low-speed and zero-speed control remains a concern.

[0027] Given the increasing adoption of electric drive systems in the auxiliary hydraulic systems of large vehicles and engineering vehicles, and addressing issues such as difficulty in low-speed control and severe load impact in auxiliary hydraulic systems, this application proposes a vehicle auxiliary drive method that is an optimal control method based on a novel multi-source hybrid auxiliary hydraulic system, effectively improving the reliability and stability of the auxiliary hydraulic system.

[0028] The implementation details of the vehicle assisted driving method in this embodiment are described below. The following content is only for the convenience of understanding and is not necessary for implementing this solution.

[0029] The vehicle-assisted driving method of this embodiment can be applied to electronic devices with communication, computing and data storage capabilities. For example, the electronic device can be a computer or an in-vehicle device (such as a control unit), etc.

[0030] This embodiment provides a vehicle assisted driving method, such as Figure 2 As shown, it includes: Step S201: Based on the pressure error between the reference value and the actual value of the outlet pressure of the hydraulic pump in the current cycle in the vehicle's auxiliary hydraulic system, the base speed of the current cycle is determined using the pressure loop controller.

[0031] The current cycle is the current control cycle.

[0032] For example, the hydraulic pumps in the auxiliary hydraulic system include steering hydraulic pumps, and may also include lifting hydraulic pumps, etc.

[0033] The hydraulic pump is driven by a hydraulic motor in an electric drive system. The hydraulic motor can be a permanent magnet motor or an asynchronous motor.

[0034] The control topology of a hydraulic motor includes an outer pressure loop. For example... Figure 3 As shown, the actual value of the hydraulic pump's outlet pressure is collected in the outer pressure ring. Reference value for calculating the outlet pressure of the hydraulic pump The difference between the actual value and the pressure error is obtained. The pressure error is input into the pressure loop controller. The pressure loop controller can be a proportional-integral (PI) controller. The pressure loop controller performs PI calculation based on the pressure error and uses the calculation result as the base speed for the current cycle. This enables stable tracking of the outlet pressure, realizes the optimal pressure control method, and improves the control accuracy at low speeds.

[0035] Step S202: Based on the change in the reference value of the outlet pressure between the current cycle and the previous cycle, the estimated value of the load flow demand of the hydraulic pump in the current cycle, and the estimated value of the system leakage flow, determine the feedforward compensation speed in the current cycle.

[0036] The load flow requirement is the flow rate required for the real-time operation of the actuator corresponding to the hydraulic pump.

[0037] The system leakage flow rate is the leakage flow rate generated by the internal gaps of the auxiliary hydraulic system.

[0038] Here, the feedforward compensation speed is a speed that compensates for the speed of the hydraulic motor by comprehensively considering the changes in the outlet pressure of the hydraulic pump, the load flow demand, and the system leakage flow, which helps to reduce load impact.

[0039] Step S203: Determine the optimal efficiency speed for the current cycle by optimizing the overall efficiency of the hydraulic motor driving the hydraulic pump and the hydraulic pump.

[0040] The optimal efficiency speed is the hydraulic motor speed at which the combined efficiency of the hydraulic motor and hydraulic pump is at its best.

[0041] Step S204: Weighted fusion of the base speed, feedforward compensation speed and optimal efficiency speed to obtain the reference value of the hydraulic motor speed for the current cycle.

[0042] In this step, the weighted coefficients corresponding to the base speed, feedforward compensation speed, and optimal efficiency speed can be used to perform a weighted summation of the base speed, feedforward compensation speed, and optimal efficiency speed to obtain a reference value for the hydraulic motor speed in the current cycle. In this way, the optimal reference value for the hydraulic motor speed can be obtained by comprehensively considering the dynamic performance and energy efficiency optimization of the system, that is, the optimal speed setting of the motor can be obtained, so as to realize the optimal control method of the auxiliary hydraulic system across the entire speed range.

[0043] Step S205: Based on the speed error between the reference value and the actual value of the hydraulic motor speed in the current cycle, the speed loop controller is used to determine the current cycle. Reference value for shaft current.

[0044] The hydraulic motor uses vector control, which decomposes the motor stator current into excitation current in a two-phase synchronous rotating coordinate system (i.e., shaft current) and torque current (i.e. (axis current) shaft and The axes are orthogonal coordinate axes.

[0045] like Figure 3 As shown, the control topology of the hydraulic motor also includes a middle-loop speed loop. In the middle-loop speed loop, the actual value of the hydraulic motor speed is collected, and a reference value for the hydraulic motor speed is calculated. Compared with actual value The speed error is input into the speed loop controller, which can be a PI controller. The speed loop controller performs PI calculations based on the input speed error and uses the result as the current cycle. Reference value of shaft current This allows for the implementation of an optimal pressure and speed control method.

[0046] Step S206: Based on the current period Reference value and actual value of shaft current Shaft current error, and based on the current cycle Reference value and actual value of shaft current Shaft current error, through Axis current loop controller and The shaft current loop controller controls the current of the hydraulic motor to drive the hydraulic pump.

[0047] like Figure 3 As shown, the control topology of the hydraulic motor also includes an inner current loop. In the inner current loop, the three-phase currents of the a, b, and c phase lines of the hydraulic motor are collected. , and Performing the Clarke transformation on the three-phase current yields... shaft current and shaft current Then to shaft current and shaft current Perform the Parker transformation to obtain Actual value of shaft current and Actual value of shaft current .Will Reference value of shaft current Compared with actual value of Shaft current error input Axis current loop controller, The shaft current loop controller uses a PI controller, based on... After performing a PI calculation on the shaft current error, we obtain... Reference value of shaft voltage .Will Reference value of shaft current Compared with actual value of Shaft current error input Axis current loop controller, The shaft current loop controller uses a PI controller, based on... After performing a PI calculation on the shaft current error, we obtain... Reference value of shaft voltage .right Reference value of shaft voltage and Reference value of shaft voltage After the inverse Parker transformation, it can be transformed into a two-phase stationary coordinate system. Reference value of shaft voltage and Reference value of shaft voltage The Space Vector Pulse Width Modulation (SVPMW) module is based on Reference value of shaft voltage and Reference value of shaft voltage A pulse signal is generated and sent to the inverter, so that the inverter outputs three-phase current to drive the hydraulic motor to rotate, thereby driving the hydraulic pump to run.

[0048] This scheme utilizes the optimal pressure and pressure-speed control method to construct a control architecture consisting of an inner current loop, a middle speed loop, and an outer pressure loop. This enables full-speed observation of both low-speed and high-speed hydraulic torque, and solves the problems of unstable, large fluctuations, and poor real-time control of low-speed hydraulic torque.

[0049] The vehicle auxiliary drive method of this embodiment determines the base speed of the current cycle based on the pressure error between the reference value and the actual value of the outlet pressure of the hydraulic pump in the vehicle's auxiliary hydraulic system during the current cycle, using a pressure loop controller. It then determines the feedforward compensation speed of the current cycle based on the change in the reference value of the outlet pressure between the current cycle and the previous cycle, the estimated load flow demand of the hydraulic pump in the current cycle, and the estimated system leakage flow. By optimizing the overall efficiency of the hydraulic motor and the hydraulic pump driving the hydraulic pump, it determines the optimal efficiency speed of the current cycle. Finally, it weights and fuses the base speed, the feedforward compensation speed, and the optimal efficiency speed to obtain the reference value of the hydraulic motor speed for the current cycle. Based on the speed error between the reference value and the actual value of the hydraulic motor speed in the current cycle, it uses a speed loop controller to determine the speed of the current cycle. Reference value for shaft current; based on the current cycle. Reference value and actual value of shaft current Shaft current error, and based on the current cycle Reference value and actual value of shaft current Shaft current error, through Axis current loop controller and The shaft current loop controller controls the current of the hydraulic motor to drive the hydraulic pump. In this way, it can comprehensively consider the hydraulic pump outlet pressure, load flow demand, system leakage status, and the overall efficiency of the hydraulic pump and hydraulic motor, dynamically optimize the reference value of the hydraulic motor speed, and realize multi-level closed-loop coordinated control of pressure loop, speed loop, and dual current loop. This avoids the situation of difficult low-speed control and severe load impact in the auxiliary hydraulic system.

[0050] In some embodiments, before obtaining a reference value for the hydraulic motor speed of the current cycle by weighted fusion of the base speed, feedforward compensation speed, and optimal efficiency speed, the vehicle auxiliary drive method further includes: determining the weight coefficient corresponding to the base speed based on the pressure error of the current cycle; determining the weight coefficient corresponding to the feedforward compensation speed of the current cycle based on the weight coefficient corresponding to the base speed; and determining the weight coefficient corresponding to the optimal efficiency speed based on the weight coefficients corresponding to the base speed and the feedforward compensation speed, respectively.

[0051] Accordingly, the reference value of the hydraulic motor speed for the current cycle is obtained by weighted fusion of the base speed, feedforward compensation speed and optimal efficiency speed, including: weighted summation of the base speed, feedforward compensation speed and optimal efficiency speed based on the weight coefficients corresponding to the determined base speed, feedforward compensation speed and optimal efficiency speed, to obtain the reference value of the hydraulic motor speed for the current cycle.

[0052] Specifically, the reference value for the current cycle hydraulic motor speed is expressed as follows: (1) in, This indicates a reference value for the hydraulic motor speed during the current cycle. Indicates the base speed of the current cycle. This indicates the feedforward compensation speed in the current cycle. This indicates the optimal efficiency rotational speed for the current cycle. This represents the weighting coefficient corresponding to the base speed in the current cycle. This represents the weighting coefficient corresponding to the feedforward compensation speed in the current cycle. This represents the weighting coefficient corresponding to the optimal efficiency rotational speed in the current cycle.

[0053] In this way, the weighting coefficients corresponding to the base speed, feedforward compensation speed and optimal efficiency speed can be dynamically and adaptively adjusted in real time according to the pressure error. By adaptively adjusting the weighting coefficients according to the working conditions, the control accuracy can be improved.

[0054] For example, the weighting coefficient corresponding to the base speed in the current cycle. for: (2) in, Indicates the current period. This indicates the current cycle pressure error. This represents the sensitivity coefficient.

[0055] Weighting coefficient corresponding to the feedforward compensation speed in the current cycle for: (3).

[0056] Weighting coefficient corresponding to the optimal efficiency speed in the current cycle for: (4).

[0057] Sensitivity coefficient This is used to adjust the sensitivity of the weighting coefficient to changes in pressure error, ensuring that the weighting coefficient adjustment process is smooth and continuous without sudden shocks.

[0058] In practical applications, the sensitivity coefficient can be adjusted as needed. .

[0059] In this embodiment, the weighting coefficients corresponding to the base speed, feedforward compensation speed, and optimal efficiency speed can be adaptively and smoothly adjusted to further improve the control effect.

[0060] In some embodiments, before determining the base speed of the current cycle using the pressure loop controller, the vehicle auxiliary drive method further includes: determining the parameters of the pressure loop controller for the current cycle based on the pressure error of the current cycle and the rate of change of the pressure error. If the pressure loop controller is a PI controller, then the parameters of the PI controller include a proportional coefficient and an integral coefficient.

[0061] For example, the current cycle ratio coefficient for: (5) in, Indicates the basic proportionality coefficient. This indicates the maximum adjustment amount of the proportional coefficient. This indicates the pressure error for the current cycle. The scale factor representing the pressure error.

[0062] Current period integral coefficient for: (6) (7) in, Indicates the integration time. This represents the initial integration time constant. This indicates the rate of change of the current periodic pressure error. This represents the maximum rate of change of pressure error. Indicates time.

[0063] The scaling factor for pressure error is used to normalize the absolute value of the pressure error to a scale of 1:1. It is a dimensionless quantity of the characteristic scale, thereby controlling the nonlinear rate at which the scaling factor increases with the increase of error.

[0064] In this embodiment, the parameters of the PI controller can be adaptively and accurately adjusted according to the rate of change of pressure error, thereby achieving parameter self-tuning of the PI controller.

[0065] For example, the base speed is calculated using the pressure ring controller according to the following formula: (8) (9) in, This represents the proportionality coefficient. Represents the integral coefficient. This represents a reference value for the outlet pressure of the hydraulic pump in the current cycle. This represents the actual value of the hydraulic pump's outlet pressure during the current cycle. This indicates the base speed of the current cycle. Indicates the duration of the period. The variable to be summed is the time step index, from the start time 0 to... Iteration, used to accumulate the pressure error for each cycle. In order to achieve the effect of integration.

[0066] The above formula can be used to track the outlet pressure and accurately output the base speed.

[0067] In some embodiments, before determining the feedforward compensation speed for the current cycle based on the change in reference value of outlet pressure between the current cycle and the previous cycle, the estimated value of load flow demand of the hydraulic pump in the current cycle, and the estimated value of system leakage flow, the vehicle auxiliary drive method further includes: calculating the estimated value of system leakage flow for the current cycle based on the pressure dynamic model of the hydraulic pump, the estimated value of load flow demand in the current cycle, and the estimated value of system leakage flow in the previous cycle.

[0068] The pressure dynamic model is an equation used to describe the change of the hydraulic pump's outlet pressure over time. The pressure dynamic model is related to the hydraulic motor speed, load flow demand, and system leakage flow.

[0069] For example, the dynamic model of pressure is represented as follows: (10) in, This represents the actual value of the hydraulic pump's outlet pressure. Indicates the rate of change in export pressure. Indicates the elastic modulus of the oil. This indicates the total volume from the pump outlet to the actuator cavity. This indicates the displacement of the hydraulic pump. Indicates the speed of the hydraulic motor. This indicates the volumetric efficiency of the hydraulic pump. Indicates load traffic demand. This indicates the system's leaked flow rate.

[0070] For example, The value is 1400 MPa. The value ranges from 0.85 to 0.95.

[0071] In this embodiment, based on the pressure dynamic model, the estimated value of leakage flow, the estimated value of current cycle load flow demand, and the estimated value of system leakage flow in the previous cycle are used to adaptively observe the system leakage flow and perform adaptive leakage compensation, thereby achieving accurate estimation of leakage flow and improving the long-term operational stability of the auxiliary hydraulic system.

[0072] In some embodiments, the estimated value of the system leakage flow in the current cycle is calculated based on the pressure dynamic model of the hydraulic pump, the estimated value of the load flow demand in the current cycle, and the estimated value of the system leakage flow in the previous cycle. This includes: calculating the flow residual based on the pressure dynamic model and the estimated value of the system leakage flow in the current cycle; calculating the product of the flow residual and the adaptive gain; and calculating the sum of the product and the estimated value of the system leakage flow in the previous cycle to obtain the estimated value of the system leakage flow in the current cycle.

[0073] Adaptive gain Used to control the correction magnitude for flow residuals. The estimated system leakage flow is relatively large, and it quickly tracks changes in actual leakage, exhibiting a fast dynamic response. The leakage flow is relatively small, the estimated value of the system leakage flow changes gradually, and the noise immunity is good. The value range is 0 to 1. The specific values ​​need to be based on The system's dynamic characteristics and noise level are determined through debugging. If the system leakage changes slowly and the sensor noise is low, a larger value can be used, such as 0.2~0.5. If the pressure signal noise is high, a smaller value should be used, such as 0.05~0.1.

[0074] In this embodiment, by calculating the flow residual, combining it with the adaptive gain, and the estimated value of the system leakage flow in the previous period, the estimated value of the system leakage flow in the current period can be accurately calculated.

[0075] For example, the estimated value of the system leakage flow in the current period is: (11) in, Indicates the current period. Indicates the previous period. This represents an estimated value of the system leakage flow rate in the previous period. This represents an estimate of the current period's load traffic demand. This represents an estimate of the system leakage flow rate during the current period. Indicates adaptive gain. The inner value represents the flow residual. This indicates the displacement of the hydraulic pump. This represents the actual value of the hydraulic motor speed. This indicates the total volume from the pump outlet to the actuator cavity. Indicates the elastic modulus of the oil; This indicates the volumetric efficiency of the hydraulic pump; This represents the actual value of the hydraulic pump's outlet pressure. The rate of change of export pressure is calculated based on a pressure dynamics model. Indicates time.

[0076] Specifically, by inputting the estimated system leakage flow rate from the previous cycle, the estimated load flow demand for the current cycle, and the actual hydraulic motor speed into the pressure dynamic model, the following calculation can be performed. .

[0077] The above formula can be used to quickly and accurately estimate the system leakage flow rate in the current cycle.

[0078] In some embodiments, determining the feedforward compensation speed for the current cycle based on the change in reference value of outlet pressure between the current cycle and the previous cycle, the estimated value of load flow demand of the hydraulic pump in the current cycle, and the estimated value of system leakage flow includes: determining a first compensation speed based on the estimated value of load flow demand of the hydraulic pump in the current cycle and the estimated value of system leakage flow; determining a second compensation speed based on the change in reference value of outlet pressure between the current cycle and the previous cycle; and determining the feedforward compensation speed for the current cycle based on the first compensation speed and the second compensation speed.

[0079] For example, the feedforward compensation speed in the current cycle is: (12) in, Indicates the current period. Indicates the previous period. This indicates the feedforward compensation speed in the current cycle. This represents an estimate of the current period's load traffic demand. This represents an estimate of the system leakage flow rate during the current period. This represents a reference value indicating current cycle export pressure. This represents a reference value indicating export pressure in the previous cycle. The change in the reference value representing export pressure. This indicates the displacement of the hydraulic pump. This indicates the volumetric efficiency of the hydraulic pump. Indicates the elastic modulus of the oil. This indicates the total volume from the pump outlet to the actuator cavity. Indicates the duration of the period.

[0080] For the first compensation speed, This is the second compensation speed.

[0081] In this embodiment, to improve dynamic response, a feedforward compensation speed is added to achieve model feedforward compensation. By accurately calculating the feedforward compensation speed, the dynamic response speed of the auxiliary hydraulic system is significantly improved.

[0082] In some embodiments, the overall efficiency includes the product of the hydraulic motor efficiency and the hydraulic pump efficiency; by optimizing the overall efficiency of the hydraulic motor driving the hydraulic pump and the hydraulic pump, the optimal efficiency speed is determined, including: determining the optimal motor speed when the hydraulic motor efficiency is optimal under the current required torque according to the motor efficiency spectrum; determining the optimal pump speed when the hydraulic pump efficiency is optimal according to the efficiency characteristics of the hydraulic pump; and weightedly fusing the optimal motor speed and the optimal pump speed to obtain the optimal efficiency speed.

[0083] In this embodiment, the efficiency of both the hydraulic motor and the hydraulic pump is optimized in a coordinated manner, overcoming the limitations of optimizing a single component. This maximizes the overall efficiency of the hydraulic motor and the hydraulic pump, effectively reducing the energy consumption of the whole machine, extending the operating time, and improving economic performance while ensuring the power requirements of hydraulic operation.

[0084] Specifically, a hydraulic motor-hydraulic pump efficiency model is constructed, and the combined efficiency of the hydraulic motor and hydraulic pump is expressed as: (13) in, Indicates overall efficiency. Indicates the efficiency of the hydraulic motor. Indicates the mechanical efficiency of the hydraulic pump. This indicates the volumetric efficiency of the hydraulic pump. This indicates the efficiency of the hydraulic pump.

[0085] The efficiency of a hydraulic motor varies with its speed and torque.

[0086] In practice, the optimal efficiency speed can be obtained by weighted summing of the optimal motor speed and the optimal pump speed. The optimal efficiency speed is: (14) in, This indicates the optimal efficiency speed. Indicates the optimal speed of the motor. Indicates the optimal pump speed. The weighting coefficient represents the optimal speed of the motor. The weighting coefficient represents the optimal pump speed.

[0087] Regarding the optimal operating point for hydraulic pump efficiency, the optimal efficiency of a hydraulic pump is typically between 70% and 90% of its rated speed. (15) in, Indicates the rated speed. This indicates the maximum allowable outlet pressure of the hydraulic pump.

[0088] The optimal speed of a hydraulic pump is not a fixed value, but varies with the outlet pressure. It varies linearly between 70% and 90% of the rated speed. When When =0, = Low voltage and light load, lower speed and higher efficiency. = hour, = High pressure and heavy load require higher speeds to maintain efficiency. The higher the load pressure, the closer the pump's optimal speed is to its rated speed, matching the operating conditions.

[0089] For example, based on the motor efficiency graph, the optimal motor speed when the hydraulic motor efficiency is optimal under the current required torque is determined, including: based on the current required torque, the rated torque of the hydraulic motor, and the current cycle base speed, selecting the motor speed that minimizes the motor loss value from all motor speeds in the motor efficiency graph as the optimal motor speed.

[0090] The motor efficiency map is also known as the motor efficiency MAP.

[0091] For example, select the motor speed that minimizes motor losses from all motor speeds in the motor efficiency graph using the following formula: (16) (17) in, This indicates the optimal motor speed for the current cycle. Indicates the base speed of the current cycle. This represents the motor speed in the motor efficiency MAP chart. Indicates the current required torque. This indicates the rated torque of the hydraulic motor. This indicates the displacement of the hydraulic pump. This represents the actual value of export pressure in the current cycle. This indicates that among all motor speeds in the motor efficiency MAP, the value that minimizes motor losses is taken. Minimum motor speed.

[0092] Based on this, in some embodiments, the optimal efficiency speed is determined by optimizing the overall efficiency of the hydraulic motor driving the hydraulic pump and the hydraulic pump. This includes: selecting the motor speed that minimizes motor losses from all motor speeds in the motor efficiency graph based on the current required torque, the rated torque of the hydraulic motor, and the current cycle base speed, as the optimal motor speed when the hydraulic motor efficiency is optimal under the current required torque; determining the optimal pump speed when the hydraulic pump efficiency is optimal based on the efficiency characteristics of the hydraulic pump; and weightedly fusing the optimal motor speed and the optimal pump speed to obtain the optimal efficiency speed.

[0093] In this embodiment, the motor speed at which the motor loss value is minimized under the current required torque is found by using the motor efficiency MAP chart. At this point, the optimal operating point of motor efficiency is found, that is, the optimal efficiency of the hydraulic motor. This enables the rapid and accurate optimization of the optimal motor speed based on the working conditions, so as to accurately correct the reference value of the hydraulic motor speed in the current cycle.

[0094] This solution targets auxiliary hydraulic systems, comprehensively considering the control architecture and methods of the inner current loop, middle speed loop, and outer pressure loop of the electric drive system. It employs an optimal control method that considers feedback from the hydraulic motor speed and hydraulic pump pressure, constructing an optimal motor speed setpoint and control method based on a pressure feedback model. The optimal motor speed setpoint control method based on pressure feedback and model compensation effectively solves the fluctuation, efficiency, and real-time control problems of electric drives for hydraulic loads. It forms a method that combines motor setpoint pressure feedforward compensation with optimal efficiency control of the motor and hydraulic pump, as well as adaptive adjustment of weighting coefficients.

[0095] It should be understood that the sequence number of each step in the above embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0096] This application also relates to a vehicle powertrain system, including: an electric drive system, the electric drive system comprising: Multiple motors, including at least one auxiliary motor, and at least one auxiliary motor including at least one hydraulic motor, the hydraulic motor being used to drive the corresponding hydraulic pump in the auxiliary hydraulic system; The control unit is used to execute the vehicle auxiliary drive method as described in any of the above embodiments for each hydraulic motor.

[0097] The auxiliary hydraulic system includes hydraulic pumps such as steering hydraulic pumps and lifting hydraulic pumps. Hydraulic motors include steering hydraulic motors for driving the steering hydraulic pumps and lifting hydraulic motors for driving the lifting hydraulic pumps.

[0098] In some embodiments, such as Figure 4 and Figure 5 As shown, the multiple motors also include at least one traction motor, and the electric drive system also includes: The DC bus includes a first DC bus on the high-voltage side and at least one second DC bus on the low-voltage side. The second DC bus is connected to the first DC bus through a corresponding DC-DC module A. The main drive system is equipped with at least one traction motor. The traction motor is connected to the first DC bus through a corresponding inverter. At least a portion of the traction motor is equipped with a corresponding first charging and discharging interface. The first charging and discharging interface is connected to the neutral point of the stator winding of the corresponding traction motor and to the negative or positive pole of the first DC bus. The auxiliary system includes at least one auxiliary motor, which is connected to a second DC bus via a corresponding inverter. At least a portion of the auxiliary motor is provided with a corresponding second charging / discharging interface, which is connected to the neutral point of the stator winding of the corresponding auxiliary motor and to the negative or positive pole of the second DC bus where the corresponding auxiliary motor is located. The first and second charging / discharging interfaces are used to connect objects to be charged or discharged.

[0099] This embodiment provides a master-slave integrated topology.

[0100] For example, the traction motor is driven by inverters connected in parallel. In this way, a high-power traction motor can be driven by two inverter modules connected in parallel.

[0101] Figure 4 The diagram shows four traction motors, denoted as TM1 to TM4, and four corresponding inverters, denoted as INU11, INU21, INU12, and INU22. INU11 and INU12 are connected in parallel to drive TM1 and TM3, while INU21 and INU22 are connected in parallel to drive TM2 and TM4.

[0102] Figure 4 The diagram shows a TM2 motor with a corresponding first charging / discharging interface. However, it is possible to set up first charging / discharging interfaces for more traction motors.

[0103] J1 and J2 are two line nodes of the first DC bus. For example... Figure 5As shown, multiple parallel second DC buses are connected to the first DC bus via corresponding DC-DC module A. DC-DC module A is used for isolation and step-up / step-down conversion. A series resistor is connected between the positive and negative terminals of the high-voltage side of DC-DC module A. The series resistor includes a fourth resistor R4 and a fifth resistor R5 connected in series. The fourth resistor R4 is connected in parallel with the first capacitor C1, and the fifth resistor R5 is connected in parallel with the second capacitor C2. A fuse F is also connected in series on the high-voltage side of DC-DC module A. An inductor L1 is connected in series with both the positive and negative terminals of the low-voltage side of DC-DC module A.

[0104] The auxiliary motor also includes a cooling fan. Figure 5 The diagram illustrates two secondary DC buses. The cooling fan is connected to one secondary DC bus via its corresponding inverter INU3. The lifting hydraulic motor is connected to the other secondary DC bus via its corresponding inverter INU4. The steering hydraulic motor is connected to the other secondary DC bus via its corresponding inverter INU5. Each of the cooling fan, lifting hydraulic motor, and steering hydraulic motor is equipped with a corresponding secondary charging / discharging interface.

[0105] The main drive system also includes a braking resistor corresponding to the traction motor. Under braking conditions, the energy fed back by the traction motor is consumed in the corresponding braking resistor. Figure 4 In the process, a first braking resistor R1 is set on the DC side of TM3, and a second braking resistor R2 is set on the DC side of TM4.

[0106] In some embodiments, the vehicle powertrain system further includes: A multi-source hybrid power unit is used to supply power to a DC bus, including: at least one engine, at least one power battery and grid wiring; The engine and power grid wiring supply power to the first DC bus, while the power battery supplies power to the corresponding second DC bus.

[0107] Among them, the power grid wiring is used to supply power to the first DC bus using the power grid.

[0108] The engine is equipped with a generator, and the engine may include at least one of a diesel engine, a gasoline engine, and a hydrogen fuel cell engine. The alternating current output from the generator is connected to the first DC bus via a corresponding rectifier unit (DRU).

[0109] The multi-source hybrid power unit and the main-auxiliary integrated topology of the above embodiments can be set up individually or in combination.

[0110] In this embodiment, a multi-source hybrid power and main-auxiliary integrated topology is provided.

[0111] Figure 4In the rectifier unit and inverter, current sensors LH are installed on the AC side and the DC side of the rectifier unit, respectively. Voltage sensors UH are also installed on the AC side and DC side of the rectifier unit. For example, the alternating current output by the generator is 0-1140V. The voltage of the first DC bus is 1600V. The voltage between the positive DC+ and negative DC- terminals of the power battery is 600V or 800V.

[0112] Figure 5 In the configuration, a current sensor LH and a voltage sensor UH are respectively installed on the low-voltage side of DC-DC module A, the AC side of the inverter, and the port of the power battery. The fourth resistor and the fifth resistor are connected in parallel with the voltage sensor UH.

[0113] The power battery port is also equipped with a fuse H.

[0114] The power battery port is also equipped with a pre-charging circuit, which includes a first contactor KM1 connected in series on the second DC bus, a third resistor R3 connected in parallel to the first contactor KM1, and a second contactor KM2 connected in series with the third resistor R3. During pre-charging, the second contactor KM2 is closed and the first contactor KM1 is open. After pre-charging is completed, the second contactor KM2 is opened and the first contactor KM1 is closed.

[0115] Traditional electric drive systems for large vehicles and construction machinery consist of a diesel engine and a generator. The three-phase AC power generated by the generator is rectified into DC power by a diode uncontrolled rectifier, and then inverted into three-phase AC power with adjustable voltage amplitude and frequency by an inverter to drive the load traction motor. However, diesel engines for large vehicles and construction machinery are characterized by heavy pollution, high energy consumption, and high cost. This embodiment provides an electric drive system topology that is compatible with multiple power sources and is suitable for high-power hybrid applications of megawatt level and above.

[0116] Traditional mining truck drive systems use a large engine as the power source for the entire vehicle. This solution uses multiple small, different power sources connected in parallel as the power input source. Different power sources can be mixed and matched to achieve modularization and miniaturization of the input of different power units. At the same time, different power units are converted to DC power supply through different power conversion devices, and different power units adopt a common DC bus design.

[0117] This solution's topology system is compatible with various power source modes, including diesel generator sets, multiple diesel generator sets, diesel-electric hybrid power, grid-connected power lines, power batteries, and hydrogen fuel cell engines. The electric drive system topology can use dual-module parallel drive for high-power electric wheels or a single module drive for a low-power transmission motor. The auxiliary and main drive systems use DC-DC modules for isolation and voltage boost / buck conversion. The DC link of the auxiliary system can be connected to the wind turbine auxiliary drive system, hydraulic pump auxiliary drive system, low-voltage battery system, and the battery system's DC cooling power output. Compared to other hybrid power systems, this vehicle power system has a wider range of compatibility and solves the problems of large power units with high power output and heavy pollution.

[0118] Based on the application conditions and road requirements of electric drive systems in large vehicles and large-scale engineering projects, multi-source hybrid electric drive systems have high power sources and multiple devices. By reusing the motor windings of the main drive system and auxiliary system, and using corresponding inverters for DC-DC boost and buck conversion, they can provide hybrid systems with flexible charging modes such as high-voltage fast charging, low-voltage slow charging, and high-low voltage hybrid charging. This reduces the equipment size, cost, and charging time of the transmission vehicles.

[0119] In practice, the first charging / discharging interface or the second charging / discharging interface is connected to the object to be charged / discharged. When the vehicle is stopped, the first contactor KM1 corresponding to the power battery is closed during charging / discharging. The inverter corresponding to the motor connected to the first charging / discharging interface or the second charging / discharging interface is used to realize the DC-DC function, thereby realizing the charging / discharging of the connected object.

[0120] This solution implements a high-voltage and low-voltage hybrid boost / buck system for the stator windings of a reused motor. The system uses a three-phase four-wire asynchronous or permanent magnet synchronous motor. The stator winding inductance of the motor and the corresponding upper and lower switching transistors of the inverter form a boost / buck circuit, reducing the need for an additional DC-DC charging / discharging module. It simultaneously provides high-voltage DC-DC functionality on the main drive's high-voltage side and low-voltage DC-DC functionality on the auxiliary drive side. Furthermore, a three-level DC-DC module is used in both the main and auxiliary systems, enabling bidirectional flow between high and low voltages. Based on this, the boost / buck system formed by the high-voltage side motor, the low-voltage side motor, and all motors can be used to charge the battery, or the battery can power external charging / discharging devices.

[0121] The electric drive system adopts a main-auxiliary integrated topology, which can drive multiple traction motors simultaneously and drive a large motor in parallel. It also has multiple auxiliary drive system circuits, which can realize the electrification of vehicle power.

[0122] This system reuses the windings of the motors in the main drive system and the auxiliary system of the electric drive system, constructing an integrated electric drive system solution based on reused motor windings. It achieves a clever flow of high and low voltage energy and control, and can realize high voltage, low voltage and mixed voltage boost and buck, while realizing energy flow in the DC link of high voltage main drive and low voltage auxiliary drive.

[0123] Another embodiment of this application relates to a vehicle auxiliary drive device. The vehicle auxiliary drive device described below can be referred to in correspondence with the vehicle auxiliary drive method described above. The implementation details of the vehicle auxiliary drive device of this embodiment are described in detail below. The following implementation details are provided only for ease of understanding and are not necessary for implementing this solution. The schematic diagram of the vehicle auxiliary drive device of this embodiment can be seen as follows: Figure 6 As shown.

[0124] This embodiment provides a vehicle auxiliary drive device for executing the vehicle auxiliary drive method as described in any of the above embodiments, such as... Figure 6 As shown, it includes: The base speed determination module 601 is used to determine the base speed of the current cycle based on the pressure error between the reference value and the actual value of the outlet pressure of the hydraulic pump in the vehicle's auxiliary hydraulic system during the current cycle, using a pressure loop controller. The compensation speed determination module 602 is used to determine the feedforward compensation speed for the current period based on the change in the reference value of the outlet pressure between the current period and the previous period, the estimated value of the load flow demand of the hydraulic pump in the current period, and the estimated value of the system leakage flow. The efficiency speed determination module 603 is used to determine the optimal efficiency speed for the current cycle by optimizing the combined efficiency of the hydraulic motor driving the hydraulic pump and the hydraulic pump. The speed fusion module 604 is used to weight and fuse the base speed, the feedforward compensation speed and the optimal efficiency speed to obtain a reference value of the hydraulic motor speed in the current cycle. The current reference determination module 605 is used to determine the current cycle based on the speed error between the reference value and the actual value of the hydraulic motor speed in the current cycle, using a speed loop controller. Reference value for shaft current; Hydraulic drive module 606, used for the current cycle as described above Reference value and actual value of shaft current Shaft current error, and based on the current cycle Reference value and actual value of shaft current Shaft current error, through Axis current loop controller and The shaft current loop controller controls the current of the hydraulic motor to drive the hydraulic pump.

[0125] It is worth mentioning that all modules involved in this embodiment are logical modules. In practical applications, a logical unit can be a physical unit, a part of a physical unit, or a combination of multiple physical units. Furthermore, to highlight the innovative aspects of this application, this embodiment does not introduce units that are not closely related to solving the technical problems proposed in this application; however, this does not mean that other units are absent in this embodiment.

[0126] Another embodiment of this application relates to an electronic device, such as... Figure 7 As shown, it includes: at least one processor 701; and a memory 702 communicatively connected to the at least one processor 701; wherein the memory 702 stores instructions executable by the at least one processor 701, the instructions being executed by the at least one processor 701 to enable the at least one processor 701 to perform the vehicle assisted driving method in the above embodiments.

[0127] The memory and processor are connected via a bus, which can include any number of interconnecting buses and bridges, connecting various circuits of one or more processors and memories. The bus can also connect various other circuits, such as peripheral devices, voltage regulators, and power management circuits, which are well known in the art and will not be described further herein. The bus interface provides an interface between the bus and the transceiver. The transceiver can be a single element or multiple elements, such as multiple receivers and transmitters, providing a unit for communicating with various other devices over a transmission medium. Data processed by the processor is transmitted over the wireless medium via an antenna, which further receives data and transmits it to the processor.

[0128] The processor manages the bus and general processing, and also provides various functions, including timing, peripheral interfaces, voltage regulation, power management, and other control functions. Memory is used to store data used by the processor during operation.

[0129] That is, those skilled in the art will understand that all or part of the steps in the methods of the above embodiments can be implemented by a program instructing related hardware. This program is stored in a storage medium and includes several instructions to cause a device (which may be a microcontroller, chip, etc.) or processor to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0130] Those skilled in the art will understand that the above embodiments are specific embodiments for implementing this application, and in practical applications, various changes can be made to them in form and detail without departing from the spirit and scope of this application.

Claims

1. A vehicle assisted drive method, characterized in that, include: Based on the pressure error between the reference value and the actual value of the outlet pressure of the hydraulic pump in the current cycle in the vehicle's auxiliary hydraulic system, the base speed of the current cycle is determined using a pressure loop controller. Based on the change in the reference value of the outlet pressure between the current cycle and the previous cycle, the estimated value of the load flow demand of the hydraulic pump in the current cycle, and the estimated value of the system leakage flow, the feedforward compensation speed in the current cycle is determined; the load flow demand is the flow required for the real-time operation of the actuator corresponding to the hydraulic pump; the system leakage flow is the leakage flow generated by the internal clearance of the auxiliary hydraulic system. The optimal efficiency speed for the current cycle is determined by optimizing the combined efficiency of the hydraulic motor driving the hydraulic pump and the hydraulic pump itself; the optimal efficiency speed is the hydraulic motor speed when the combined efficiency of the hydraulic motor and the hydraulic pump is optimal. The reference value of the hydraulic motor speed for the current cycle is obtained by weighted and fused the base speed, the feedforward compensation speed, and the optimal efficiency speed. Based on the speed error between the reference value and the actual value of the hydraulic motor speed in the current cycle, the speed loop controller is used to determine the current cycle. Reference value for shaft current; Based on the current cycle Reference value and actual value of shaft current Shaft current error, and based on the current cycle Reference value and actual value of shaft current shaft current error, through Axis current loop controller and The shaft current loop controller controls the current of the hydraulic motor to drive the hydraulic pump.

2. The vehicle assisted driving method according to claim 1, characterized in that, Before obtaining a reference value for the current cycle hydraulic motor speed by weighted fusion of the base speed, the feedforward compensation speed, and the optimal efficiency speed, the process further includes: Based on the pressure error of the current cycle, determine the weighting coefficient corresponding to the base rotation speed; Based on the weighting coefficient corresponding to the base rotation speed, determine the weighting coefficient corresponding to the feedforward compensation rotation speed in the current cycle; Based on the weighting coefficients corresponding to the base speed and the feedforward compensation speed, the weighting coefficient corresponding to the optimal efficiency speed is determined. The weighted fusion of the base speed, the feedforward compensation speed, and the optimal efficiency speed to obtain a reference value for the hydraulic motor speed in the current cycle includes: Based on the determined weighting coefficients corresponding to the base speed, the feedforward compensation speed, and the optimal efficiency speed, the base speed, the feedforward compensation speed, and the optimal efficiency speed are weighted and summed to obtain a reference value for the hydraulic motor speed in the current cycle.

3. The vehicle assisted driving method according to claim 1, characterized in that, The overall efficiency includes the product of the hydraulic motor efficiency and the hydraulic pump efficiency; The step of determining the optimal efficiency speed by optimizing the combined efficiency of the hydraulic motor driving the hydraulic pump and the hydraulic pump itself includes: determining the optimal motor speed when the hydraulic motor has the best efficiency under the current required torque based on the motor efficiency graph; determining the optimal pump speed when the hydraulic pump has the best efficiency based on the efficiency characteristics of the hydraulic pump; and weightedly fusing the optimal motor speed and the optimal pump speed to obtain the optimal efficiency speed; or... The step of determining the optimal efficiency speed by optimizing the overall efficiency of the hydraulic motor driving the hydraulic pump and the hydraulic pump includes: selecting the motor speed that minimizes motor losses from all motor speeds in the motor efficiency graph based on the current required torque, the rated torque of the hydraulic motor, and the base speed of the current period, as the optimal motor speed when the hydraulic motor efficiency is optimal under the current required torque; determining the optimal pump speed when the hydraulic pump efficiency is optimal based on the efficiency characteristics of the hydraulic pump; and weightedly fusing the optimal motor speed and the optimal pump speed to obtain the optimal efficiency speed.

4. The vehicle assisted driving method according to claim 1, characterized in that, The determination of the feedforward compensation speed for the current period, based on the change in the reference value of the outlet pressure between the current period and the previous period, the estimated value of the load flow demand of the hydraulic pump in the current period, and the estimated value of the system leakage flow, includes: Based on the estimated load flow demand of the hydraulic pump in the current cycle and the estimated system leakage flow, the first compensation speed is determined; The second compensation speed is determined based on the change in the reference value of the outlet pressure between the current cycle and the previous cycle. Based on the first compensation speed and the second compensation speed, the feedforward compensation speed for the current cycle is determined.

5. The vehicle assisted driving method according to claim 1, characterized in that, Before determining the feedforward compensation speed for the current period, based on the change in the reference value of the outlet pressure between the current period and the previous period, the estimated value of the hydraulic pump load flow demand for the current period, and the estimated value of the system leakage flow, the following steps are also included: Based on the pressure dynamic model of the hydraulic pump, the estimated value of the load flow demand in the current period, and the estimated value of the system leakage flow in the previous period, the estimated value of the system leakage flow in the current period is calculated. The pressure dynamic model is an equation used to describe the change of the outlet pressure of the hydraulic pump over time. The pressure dynamic model is related to the hydraulic motor speed, load flow demand, and system leakage flow.

6. The vehicle assisted driving method according to claim 5, characterized in that, Based on the pressure dynamic model of the hydraulic pump, the estimated load flow demand for the current period, and the estimated system leakage flow for the previous period, the estimated system leakage flow for the current period is calculated, including: calculating the flow residual based on the pressure dynamic model and the estimated system leakage flow for the current period; calculating the product of the flow residual and the adaptive gain; and summing the product with the estimated system leakage flow for the previous period to obtain the estimated system leakage flow for the current period; or, The estimated value of the system leakage flow rate for the current period is: in, Indicates the current period. Indicates the previous period. This represents an estimated value of the system leakage flow rate from the previous period. This represents an estimate of the load traffic demand for the current period. This represents an estimated value of the system leakage flow rate for the current period. Indicates adaptive gain. The inner value represents the flow residual. This indicates the displacement of the hydraulic pump. This represents the actual value of the hydraulic motor's rotational speed. This indicates the total volume from the pump outlet to the actuator cavity. Indicates the elastic modulus of the oil; This indicates the volumetric efficiency of the hydraulic pump; This represents the actual value of the hydraulic pump's outlet pressure. The rate of change of the outlet pressure is calculated based on the pressure dynamic model. Indicates time.

7. The vehicle assisted driving method according to claim 2, characterized in that, The weighting coefficient corresponding to the base speed in the current period for: in, Indicates the current period. This indicates the pressure error in the current cycle. Indicates the sensitivity coefficient; The weighting coefficient corresponding to the feedforward compensation speed in the current cycle for: The weighting coefficient corresponding to the optimal efficiency speed in the current cycle for: 。 8. The vehicle assisted driving method according to claim 4, characterized in that, The feedforward compensation speed for the current cycle is: in, Indicates the current period. Indicates the previous period. This indicates the feedforward compensation speed in the current cycle. This represents an estimate of the load traffic demand for the current period. This represents an estimated value of the system leakage flow rate for the current period. This represents a reference value for the export pressure in the current cycle. This represents a reference value for the export pressure mentioned in the previous period. This indicates the change in the reference value of the outlet pressure. This indicates the displacement of the hydraulic pump. This indicates the volumetric efficiency of the hydraulic pump. Indicates the elastic modulus of the oil. This indicates the total volume from the pump outlet to the actuator cavity. Indicates the duration of the period; This is the first compensation speed. This is the second compensation speed.

9. The vehicle assisted driving method according to claim 1, characterized in that, Before determining the base speed of the current cycle using the pressure loop controller, the method further includes: determining the parameters of the pressure loop controller for the current cycle based on the pressure error and the rate of change of the pressure error in the current cycle, wherein the pressure loop controller is a proportional-integral controller and the parameters of the proportional-integral controller include a proportional coefficient and an integral coefficient. The proportional coefficient mentioned in the current period for: in, Indicates the basic proportionality coefficient. This indicates the maximum adjustment amount of the proportional coefficient. Indicates the current period. This indicates the pressure error for the current cycle. The scale factor representing the pressure error; The integral coefficients of the current period for: in, Indicates the integration time. This represents the initial integration time constant. This represents the rate of change of the current periodic pressure error. This represents the maximum rate of change of pressure error; Indicates time.

10. A vehicle powertrain system, characterized in that, include: An electric drive system, the electric drive system comprising: Multiple motors, including at least one auxiliary motor, the at least one auxiliary motor including at least one hydraulic motor, the hydraulic motor being used to drive a corresponding hydraulic pump in an auxiliary hydraulic system; A control unit, the control unit being configured to perform the vehicle auxiliary drive method as described in any one of claims 1 to 9 for each of the hydraulic motors.

11. The vehicle power system according to claim 10, characterized in that, The plurality of motors further includes at least one traction motor. The electric drive system further includes: a DC bus, the DC bus including a first DC bus on the high-voltage side and at least one second DC bus on the low-voltage side, the second DC bus being connected to the first DC bus via a corresponding DC-DC module; a main drive system, the main drive system including the at least one traction motor, the traction motor being connected to the first DC bus via a corresponding inverter, at least a portion of the at least one traction motor being provided with a corresponding first charging / discharging interface, the first charging / discharging interface being connected to the neutral point of the stator winding of the corresponding traction motor and to the negative or positive terminal of the first DC bus; an auxiliary system, the auxiliary system including at least one auxiliary motor, the auxiliary motor being connected to a second DC bus via a corresponding inverter, at least a portion of the at least one auxiliary motor being provided with a corresponding second charging / discharging interface, the second charging / discharging interface being connected to the neutral point of the stator winding of the corresponding auxiliary motor and to the negative or positive terminal of the second DC bus where the corresponding auxiliary motor is located; the first charging / discharging interface and the second charging / discharging interface are used to connect to a charging / discharging object; and / or, The vehicle powertrain system further includes a multi-source hybrid power unit; the multi-source hybrid power unit is used to supply power to the DC bus, and includes at least one engine, at least one power battery and grid wiring; the engine and the grid wiring supply power to the first DC bus, and the power battery supplies power to the corresponding second DC bus.

12. A vehicle auxiliary drive device, characterized in that, include: The base speed determination module is used to determine the base speed for the current cycle based on the pressure error between the reference value and the actual value of the outlet pressure of the hydraulic pump in the vehicle's auxiliary hydraulic system during the current cycle, using a pressure loop controller. The compensation speed determination module is used to determine the feedforward compensation speed for the current cycle based on the change in the reference value of the outlet pressure between the current cycle and the previous cycle, the estimated value of the load flow demand of the hydraulic pump in the current cycle, and the estimated value of the system leakage flow. The load flow demand is the flow required for the real-time operation of the actuator corresponding to the hydraulic pump; the system leakage flow is the leakage flow generated by the internal clearance of the auxiliary hydraulic system. The efficiency speed determination module is used to determine the optimal efficiency speed for the current cycle by optimizing the overall efficiency of the hydraulic motor driving the hydraulic pump and the hydraulic pump; the optimal efficiency speed is the hydraulic motor speed when the overall efficiency of the hydraulic motor and the hydraulic pump is optimal. The speed fusion module is used to weight and fuse the base speed, the feedforward compensation speed and the optimal efficiency speed to obtain a reference value of the hydraulic motor speed in the current cycle. The current reference determination module is used to determine the current cycle based on the speed error between the reference value and the actual value of the hydraulic motor speed in the current cycle, using the speed loop controller. Reference value for shaft current; The hydraulic drive module is used to drive the system based on the current cycle. Reference value and actual value of shaft current Shaft current error, and based on the current cycle Reference value and actual value of shaft current shaft current error, through Axis current loop controller and The shaft current loop controller controls the current of the hydraulic motor to drive the hydraulic pump.

13. An electronic device, characterized in that, include: At least one processor; as well as, A memory communicatively connected to the at least one processor; wherein, The memory stores instructions that can be executed by the at least one processor to enable the at least one processor to perform the vehicle assisted drive method as described in any one of claims 1 to 9.

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